Capacitor module and capacitor battery comprising the same

ABSTRACT

A capacitor module ( 1 ) is proposed, in which a first ( 10 A) and a second capacitor ( 10 B) are located, in each instance, in separate, metallically conductive housings ( 5 A,  5 B) that are tightly sealed from one another. The two housings are connected with one another by way of a contact surface, wherein an internal electrical circuit comes about. Each housing has at least one first connector ( 2 A,  2 B) that is electrically insulated from the housing, in each instance. Because of the direct electrical connection between the two capacitors, a capacitor module according to the invention requires fewer screw connections and thereby can be produced in simpler and more cost-advantageous manner.

In the case of capacitors, for example double-layer capacitors, the cellvoltage is limited to a few volts. Since, in the case of mostapplications, the operating voltages are significantly higher, severalcapacitors have to be connected in series to produce a capacitor module.In the case of conventional capacitor modules, individual capacitors areconnected with additional capacitors by way of current rails, by meansof screw connections (see FIG. 1). Such conventional capacitor moduleshave the disadvantage that because of the numerous screw connections, asignificant expenditure of assembly effort is required; this is verytime-intensive and cost-intensive, and increases the internal resistanceof the capacitor module.

It is the aim of the present invention to provide a capacitor modulethat is improved with reference to the aforementioned disadvantages.

This aim is achieved, according to the invention, by means of acapacitor module as recited in claim 1. Advantageous embodiments of thecapacitor module, as well as a capacitor battery having the capacitormodule, are the object of dependent claims.

The invention relates to a capacitor module in which a first and asecond capacitor are each located in separate, metallically conductivehousings that are tightly sealed from one another. Each of the housingsrepresents a pole of the capacitors, in each instance, wherein the twohousings are directly connected with one another by way of a mutualcontact surface, with at least a partial positive lock. In thisarrangement, an internal electrical circuit comes about. Each capacitorhas at least one first connector, in each instance, for externalelectrical contacting of the module, which connector is electricallyinsulated from the housing.

The advantage of a capacitor module according to the invention includesthe fact that the two electrically conductive housings, in which thecapacitors are accommodated, in each instance, directly touch oneanother by way of a contact surface. Since there is a direct electricalconnection between the two housings (see FIG. 2), those screwconnections that served for contacting between the two capacitors untilnow, in the case of conventional capacitor modules (see FIG. 1), can beeliminated. For this reason, capacitor modules according to theinvention can be produced more cost-effectively than conventionalmodules, with less assembly effort. Furthermore, capacitor modulesaccording to the invention also have a lower weight, as well as a lowerinternal resistance, than conventional capacitor modules, and this has aparticularly advantageous effect on the use of the capacitor modulesaccording to the invention in automotive applications, for example inautomobiles. Because of the close thermal coupling of the two capacitorsin the capacitor module according to the invention, the differentspontaneous discharge behavior of the two capacitors is also balancedout, at least in part, so that the complicated measures for making thevoltage symmetrical, as mentioned above, are eliminated in the case ofcapacitor modules according to the invention. The direct contact betweenthe two metallically conductive housings therefore makes a particularlysimple serial circuit of capacitors possible, in a capacitor moduleaccording to the invention. The capacitor housings are tightly sealedfrom one another and separated, in order to assure that the electrolyteis not exposed to any overly high electrical voltage.

The first connectors, which are electrically insulated from the housing,generally serve to contact the capacitors located in the housing, whichare present, for example, in the form of capacitor films. Capacitorsgenerally consist of two electrode layers, between which a porousseparator is arranged. Both the separator and the electrode layer are incontact with an electrolyte solution. The layer arrangements of theelectrode layers and the separators can be rolled up to producecapacitor coils.

In another embodiment of the invention, the capacitor module has atleast one second electrical connector, connected with the housing in anelectrically conductive manner. In this way it is possible to alsoelectrically contact the capacitor housing, which has a differentpotential applied to it from that of the capacitor, so that in the caseof a capacitor module according to the invention, parallel circuits ofcapacitors are also possible.

In another advantageous embodiment of the invention, the housings of thecapacitors have a rectangular cross-section, in each instance. Thismeans that the housing is rectangular. However, it is also possible thatthe housings are flattened off or rounded off at the corners.Rectangular housings can be accommodated in capacitor modules in aparticularly space-saving manner.

In the case of another advantageous variant of the invention, the twohousings are arranged in the capacitor module at least partly with apositive lock, so that a contact surface is formed between two housings.This has the advantage that because of a large contact surface, aparticularly good electrical connection comes about between two housingsin the capacitor module according to the invention.

In another embodiment, the housings each have a round cross-section.This means that the capacitor housings are shaped cylindrically, forexample. In the case of this variant, the flat bottoms of the twohousings can be connected with a metal plate, in an electricallyconductive manner. This means that in the case of cylindrical housings,an electrical connection comes about not only by means of directcontacting of the two housings, but also, additionally, by means of anelectrically conductive plate that is connected with the two housings inan electrically conductive manner.

Furthermore, it is possible that in the case of cylindrical housings,the bottoms of the two housings are arranged with at least a partialpositive lock, and therefore can form a contact surface if they areappropriately arranged coaxially one behind the other. In this manner, aparticularly large contact surface comes about, even in the case ofcylindrical housings of a capacitor module according to the invention,and this allows for a particularly good electrical connection betweenthe two capacitors.

It is furthermore possible that all the electrical connectors arearranged on the same surface of the capacitor module. This so-calledradial construction allows for a particularly cost-effective structureof capacitor modules, at a low installation volume, since the capacitorsare contacted only from one side.

In another advantageous variant of a capacitor module according to theinvention, the two housings are welded to one another. This has theadvantage that a particularly good and permanent electrical connectionbetween the two housings comes about, which connection can alsowithstand mechanical stress. Furthermore, welding also offers protectionagainst oxidation of the contact surface.

It is also possible to screw the two capacitor housings together, forexample, or to connect them with one another by accommodating them in asingle larger housing.

If at least one capacitor module according to the invention is connectedwith other capacitor modules and/or capacitors, this results in acapacitor battery. Generally, the individual modules or individualcapacitors in a capacitor battery are connected in series. A capacitorbattery having capacitor modules according to the invention has theadvantage, as is also the case when connecting individual capacitors inseries, that half of the screw connections and the related problems, forexample the great assembly effort, can be eliminated.

In the following, the invention will be explained in greater detail,using exemplary embodiments and their figures.

FIG. 1 shows a conventional capacitor module,

FIG. 2 shows a variant of a capacitor module according to the invention.

FIGS. 3A and 3B show a variant of a capacitor module according to theinvention in cross-section and in a top view, in which the capacitors,in each instance, are contacted axially.

FIGS. 4A and 4B show another variant of a capacitor module according tothe invention, in a perspective view and in a top view, in which thecapacitors, in each instance, are contacted radially.

FIG. 5 shows an advantageous embodiment of a capacitor module accordingto the invention, with tube-shaped capacitor housings.

FIG. 6 shows a capacitor battery in which two capacitor modulesaccording to the invention are connected together.

FIG. 1 shows a conventional capacitor module, in which the housings 5Aand 5B of the individual capacitors 10A and 10B do not make directcontact. The individual capacitors 10A and 10B can be present, forexample, in the form of capacitor coils. These capacitor coils contactfirst electrical connectors 2A and 2B, in each instance, which are eachelectrically insulated from the capacitor housings, in each instance, bymeans of insulation rings 6A or 6B. These first electrical connectorscontact a first electrode film in the capacitor coils. The secondelectrode film in the capacitor coils, in each instance, contacts thesecond electrical connectors 4A and 4B, respectively, which areconnected with the capacitor housings, in each instance, in anelectrically conductive manner. The capacitor housings therefore have apotential applied to them. Electrical contacting between the twocapacitors of the conventional capacitor module therefore takes place byway of the contact plate 11A and corresponding screw connections betweenthe electrical connectors 4A and 2B. As already described above, thisconventional method of contacting is very time-consuming andmaterial-intensive, and therefore also cost-intensive.

FIG. 2 shows a variant of a capacitor module 1 according to theinvention, in which the two capacitor housings 5A and 5B have arectangular cross-section. The two housings contact one another by wayof their side surfaces, so that a contact surface is formed that allowsa direct electrical connection between the two capacitor housings andtherefore also between the two capacitors 10A and 10B. In this process,an electrode film of the capacitors, in each instance, which are shownas capacitor coils here, as an example, contacts the first electricalconnectors 2A and 2B, in each instance, and the latter are electricallyinsulated from their housings, in each instance, by means of theinsulation rings 6A and 6B. The second electrode films of the capacitorcoils 10A and 10B, in each instance, contact their housings, in eachinstance, by way of the contact points 3A and 3B, so that the housingshave the potential of the second electrode film applied to them. Acomparison of FIGS. 1 and 2 makes it clear that the contacting betweenthe capacitors and the two connectors 4 a and 2 b that is provided bythe additional contact plate 11A can be eliminated in the case ofcapacitor modules according to the invention.

FIG. 3 a shows a variant of a capacitor module according to theinvention, in cross-section, in which the capacitor coils, which areaccommodated in rectangular housings, are contacted axially. This meansthat the two electrode films of each capacitor coil are contacted onopposite faces of the housing. In this case, one electrode film contactsthe connectors 2A and 2B, in each instance, while the other electrodefilm contacts the housing by way of the contact points 3A and 3B.

FIG. 3B shows the capacitor module shown in FIG. 3A in cross-section, ina top view. The first electrical connectors 2A and 2B, in each instance,can be seen; they are insulated from their housings, in each instance,by means of the insulation disks 6A and 6B, in each instance.

FIG. 4 a shows an embodiment of a capacitor module according to theinvention in a perspective view, in which the electrode films of thecapacitor coils 10A and 10B are contacted radially. This means that thetwo electrode films in a capacitor are contacted on the same side oftheir electrical connector, i.e., of the housing. In this embodiment,the electrode films of the capacitor coil, in each instance, contact thefirst electrical connectors 2A and 2B, respectively, or the contactingpoints 7A and 7B, respectively, with their housings, in each instance.Such capacitor modules having rectangular capacitor housings and radialcontacting allow for a particularly space-saving structure of capacitorbatteries.

FIG. 4B shows a top view of the capacitor module according to theinvention shown in FIG. 4A in a perspective view. The first electricalconnectors 2A and 2B; respectively, and the contacting points 7A and 7Bfor the housing can be seen, in each instance.

FIG. 5 shows another embodiment of a capacitor module according to theinvention, having two coaxial, cylindrical capacitor housings 5A and 5B.It can be seen that in the case of this variant, the capacitor housingscontact one another by way of their bottoms, which are formed to beflat, in each instance, with a positive lock. In the case of tube-shapedcapacitor housings, the flat upper and lower ends of the tubes arereferred to as bottoms. This method of contacting allows for aparticularly large contact surface between the two housings andtherefore a particularly good electrical connection, in the case oftube-shaped capacitor housings.

FIG. 6 shows a capacitor battery in which two capacitor modulesaccording to the invention are connected in series. The electricalpotentials of the first electrical connectors, in each instance, or ofthe contacting points to the housing, are designed for serialconnection, as an example. Such a capacitor battery requiressignificantly fewer screw connections than conventional capacitorbatteries. Each of the two housings (5A, 5B) represents a pole of one ofthe capacitors (10A, 10B), in each instance. The two housings aredirectly connected with one another by way of a mutual contact surface,at least partly with a positive lock, bringing about an internalelectrical circuit. In this arrangement, the two capacitors (10A, 10B)have a different poling relative to their housings, inverse to oneanother, in each instance, resulting in an internal serial connection ofthe two capacitors (10A, 10B).

Further variations of a capacitor module according to the invention arefurthermore possible, in the case of the embodiments of the capacitors,which can also consist of layer stacks that are not rolled up, forexample, instead of the capacitor coils shown here.

1. A capacitor module comprising: a first housing for holding a firstcapacitor, the first housing being conductive and corresponding to apole of the first capacitor, the first housing comprising a firstcontact surface; and a second housing for holding a second capacitor,the second housing being conductive and corresponding to a pole of thesecond capacitor, the second housing comprising a second contactsurface; wherein the first housing and the second housing aresubstantially sealed from one another; wherein the first contact surfaceand the second contact surface contact one another and are lockedtogether resulting in formation of an electrical circuit; and whereineach of the first capacitor and the second capacitor comprises anexternal contact that is electrically insulated from the first housingor the second housing.
 2. The capacitor module of claim 1, wherein thefirst and second capacitors have inverse poles; and wherein theelectrical circuit comprises a series circuit that includes the firstand second capacitors.
 3. The capacitor module of claim 1, furthercomprising: a first electrical contact between the first housing and thefirst capacitor; and a second electrical contact between the secondhousing and the second capacitor.
 4. The capacitor module of claim 1,wherein the first housing and the second housing each have across-section that is substantially rectangular.
 5. The capacitor moduleof claim 1, wherein each of the first and second housings has across-section that is substantially round; and wherein the first andsecond housings comprise bottoms that are connected with a metal plateresulting in an electrical connection.
 6. The capacitor module of claim1, wherein the first housing and the second housing each have across-section that is substantially round; and wherein the first andsecond housings comprise bottoms that are arranged to form at least apartial positive lock, where a bottom of the first housing comprises thefirst contact surface and a bottom of the second housing comprises thesecond contact surface.
 7. The capacitor module of claim 1, wherein allelectrical connections between the first housing and the second housingare on a mutual contact surface of the first and second housings.
 8. Thecapacitor module of claim 1, wherein the first housing and the secondhousing are welded to one another.
 9. A capacitor battery comprising: atleast one capacitor module according to claim 1 connected to anothercapacitor module according to claim 1 and/or to a capacitor.
 10. Thecapacitor module of claim 2, further comprising: a first electricalcontact between the first housing and the first capacitor; and a secondelectrical contact between the second housing and the second capacitor.11. The capacitor module of claim 2, wherein the first housing and thesecond housing each have a cross-section that is substantiallyrectangular.
 12. The capacitor module of claim 2, wherein each of thefirst and second housings has a cross-section that is substantiallyround; and wherein the first and second housings comprise bottoms thatare connected with a metal plate resulting in an electrical connection.13. The capacitor module of claim 2, wherein the first housing and thesecond housing each have a cross-section that is substantially round;and wherein the first and second housings comprise bottoms that arearranged to form at least a partial positive lock, where a bottom of thefirst housing comprises the first contact surface and a bottom of thesecond housing comprises the second contact surface.
 14. The capacitormodule of claim 2, wherein all electrical connections between the firsthousing and the second housing are a mutual contact surface of the firstand second housings.
 15. The capacitor module of claim 2, wherein thefirst housing and the second housing are welded to one another.
 16. Acapacitor module comprising: a first housing for holding a firstcapacitor, the first housing being conductive, the first housingcomprising a first contact surface; and a second housing for holding asecond capacitor, the second housing being conductive, the secondhousing comprising a second contact surface; wherein the first contactsurface and the second contact surface contact one another and arelocked together resulting in formation of an electrical circuit; andwherein each of the first capacitor and the second capacitor comprisesan external contact that is electrically insulated from the firsthousing or the second housing.
 17. The capacitor module of claim 16,wherein the first housing and the second housing each have across-section that is substantially round; and wherein the first andsecond housings comprise bottoms that are arranged to form at least apartial positive lock, where a bottom of the first housing comprises thefirst contact surface and a bottom of the second housing comprises thesecond contact surface.
 18. The capacitor module of claim 16, whereinall electrical connections between the first housing and the secondhousing are a mutual contact surface of the first and second housings.19. The capacitor module of claim 16, wherein the first housing and thesecond housing are welded to one another.
 20. The capacitor module ofclaim 16, wherein the first and second capacitors have different poles.